Myoglianin regulates the insulin signaling pathway, altering glycolipid metabolism and affecting Locusta migratoria diapause

Diapause is a physiological adaptation regulated by both environmental and genetic factors that occurs at specific developmental stages in each species. There are few reports on the molecular regulatory mechanisms of nymphal diapause in Locusta migratoria. As an agricultural pest, this species has evolved wings and migratory abilities, making it particularly crucial to prevent the locust from remaining in its nymphal stage or inducing diapause during this phase. Myoglianin (Myo) plays a role in regulating insect development. Nevertheless, the functional significance of the Myo remains unclear, particularly regarding its regulation of diapause. In this study, the LmMyo gene was identified and tissue-specific analyses revealed high expression levels of LmMyo in the head. Knocking out of Myo resulted in 68-72 % of locusts remaining in the nymphal stage. Additionally, the duration of the nymphal development period was significantly altered. Silencing of LmMyo altered the contents of ILP, 20E and JH, inhibited the phosphorylation of the FOXO protein, and affected cell proliferation in the different nymph development stages. Transcriptome analyses and metabolic indicators related to glucose and lipid metabolism revealed that the knockdown of Myo can alter glucose and lipid metabolism. Furthermore, the reinjection of Insulin after interference with dsLmMyo can partially rescue the molting of locusts. Collectively, Myo can regulate glucose and lipid metabolism by influencing the FOXO-dependent Insulin pathway, which impacts diapause. This discovery enhances our understanding of nymphal diapause and presents a promising target for the control of agricultural pests.

Glycolipid metabolism; Insulin signaling pathway; Myoglianin.